Filmmaker Penelope Jagessar Chaffer was curious about the chemicals she was exposed to while pregnant: Could they affect her unborn child? So she asked scientist Tyrone Hayes to brief her on one he studied closely: atrazine, a herbicide used on corn. (Hayes, an expert on amphibians, is a critic of atrazine, which displays a disturbing effect on frog development.) Onstage together at TEDWomen, Hayes and Chaffer tell their story.

Penelope Jagessar Chaffer is the director and producer of the documentary/surrealist film Toxic Baby. She works to bring to light the issue of environmental chemical pollution and its effect on babies and children.

Tyrone Hayes, professor at the University of California, Berkeley, studies frogs and other amphibians in ponds around the world. He's become an active critic of the farm chemical atrazine, which he's found to interfere with the development of amphibians' endocrine systems. Hayes is the subject of the chidren's book The Frog Scientist, and lectures frequently. His work was recently covered in Mother Jones.